Preparation of beta-lactones



Patented Sept. 28, 1948 i PREPARATION OF BETA-LACTONES John R. Caldwell,Kingsport, Tenn., assignor to Eastman Kodak Company, Rochester, N. Y., acorporation of New Jersey No Drawing. Application July 23, 1947, SerialNo. 763,149

This invention relates to an improved process ,for preparingbeta-lactones of beta-hydroxy carboxylic acids by reacting a ketene withcarbonylcontaining compounds, such as aldehydes, ketones, diketones andketoesters, hereinafter 'referred to as carbonyl compounds.

Staudinger first showed that keto-ketenes, such as diphenyl ketene,react with aldehydes and ketones to give lact'ones (Annalen 384, 1911,pages 38 to 135 and Annalen 380, 1911, page 243), and with unsaturatedketones to give unsaturated hydrocarbons (Annalen 401, 1913, page 263).It has long been known that aldo-ketenes, such as methyl ketene, readilypolymerize to the dimer under ordinary conditions of temperature andpressure. Boese in U. S. Patent No. 2,108,427, dated February 15, 1939,shows that ketene dimers react with aldehydes to produce unsaturatedketones. The process of my invention, however, is applicable both toaldoand keto-ketenes although ketene itself is usually preferred.

Kung in U. S. Patent No. 2,356,459, dated August 22, 1944, shows thereaction between'ketenes and aldehydes and ketones to producebeta-lactones, a catalyst of the Friedel-Crafts type being employed.Gwynn and Degering in U. S, Patent 2,383,965, dated September 4, 1945,show that ketene reacts with ketones in the presence of acid catalyststo produce enol esters. In view of the teaching by the prior art thatacid-type catalysts ordinarily produce'enol esters when ketene reactswith a ketone, it was most surprising to find that the present catalystslead to the formation of beta-lactones instead.

An object of the present invention is to provide an improved process forpreparing beta-lactones by reacting a ketene with a carbonyl compoundwhereby yields of '75 to 85% may be attained.

A further object of the present invention is to provide an improvedprocess for preparing betalactones by reacting a ketene with acarbonylcontainin-g compound in the presence of a catalyst comprising ametallic salt of perchloric acid. Other objects will become apparentfrom a consideration of the following examples.

Aldehydes which may be utilized in my invention are representedby theformula:

where R stand for hydrogen; an alkyl radical, such as methyl, ethyl,propyl, butyl, secondary 19 Claims. (01. 260 344) 2 butyl and tertiarybutyl radicals, i. e., an alkyl group of the formula CnH2n+1 where nis ap'ositive integer of 1 to 4; an aralkyl radical, such as benzyl orbeta-phenyl ethyl; and an aryl group such as phenyl, ortho, meta, andpara tolyl, i. e., an aryl radical of the benzene series having 6 to 10carbon atoms. Aldehydes where R is hydrogen or methyl arepreferred forthe purpose of my invention. However, other aldehydes may likewise be'employed.

Ketones'which may be employed in my process have the formula:

wherein R. and R represent the same or different alkyl groups, such'asmethyl, ethyl, propyl, butyl, secondary-and tertiary butyl, i. e., analkyl radical having the formula ChH2n+1, where n is a positive'integerfrom 1 to 4; an aryl group, such asphenyl, ortho-, meta-, andpara-tolyl, i. e., an aryl group of the benzene series having 6 to 10carbon atoms or an aralkyl group, such as benzyl or beta-phenyl ethyl.Acetone is the preferred ketone due to'its commercial availability.However, other ketones may likewise b used expeditiousl'y.

The diketones whichI prefer'to use in my process have thefo'rmulazwherein R3 and R4 represent an alkyl radical, such as methyl, ethyl,propyl, i-s'op'ropyl, butyl, secondary andtertiary butyLi. e., an alkylradical of the formula CnH2n+1 wherein 'n is a positive integer of 1' to'4, and m represents a positive integer of 1 to 5. 7

Suitable keto-esters which may be used have the formula:

wherein-R5 andRs' represent the same or different alkyl radicals, suchas methyL'ethyl, propyl, isopropyl, butyl, secondary and tertiary butyl,and m is a positive integer from 1 to 5.

Typical carbonyl compounds which may be used in practicing my inventionare formaldehyde, "acet'aldehyde, propionaldehyde, butyraldehyde,isobutyr'aldehyde, benzaldehyde, phenylac'etal'dehyde, beta 'phenylpropion'aldehyde, 'tolyl aldehyde, acetone, diethyl k'etone, methylethyl keto-ne, methyl propyl ketone, methyl butyl ketone, acetophenone,benzophenone, methyl benzyl ketone, paramethyl acetophenone, biacetyl,acetyl acetone, hexandione 2,4, methyl pyruvate, ethyl pyruvate, methyland ethyl acetoacetates, methyl and ethyl levulinates and the like. Inaddition, compounds not set forth in the above formulae, such ascrotonaldehyde, furfuraldehyde, methyl cyclohexyl ketone, methylisopropenyl ketone, and other olefinic ketones or aldehydes likewise maybe employed.

Ketenes which may be employed in my invention have the formula:

o=o=o 8 wherein R7 and Rs represent hydrogen, the same or differentalkyl radicals, such as methyl, ethyl, propyl, isopropyl, butyl,secondary and tertiary butyl, i. e., an alkyl radical having 1 to 4carbon atoms, an aryl radical, such as phenyl, ortho-, meta-, andpara-tolyl, i. e., an aryl radical of the benzene series having 6 to 10carbon atoms or an aralkyl radical, such as benzyl, beta phenyl ethyland the like. Ketenes where R7 and Rs are hydrogen or a methyl radicalrepresent a preferred group.

Generally any metallic salt of perchloric acid may be used as acatalyst. The metals of groups II and VIII of the periodic system arepreferred, and I may use the salts of such metals as iron, cobalt,nickel, zinc, cadmium, calcium, stannous tin and the like. Othermetallic salts, such as the sodium, potassium, and cupric perchloratesmay be used. The amount of catalyst may be varied with the type ofcarbonyl compound being used, and amounts of catalyst may vary from0.01% to 2% based on the weight of the carbonyl compound. For practicalpurposes an amount of catalyst of from 0.1% to 0.5% based on the weightof the carbonyl compound may be used.

The temperature of my process may likewise be varied according to thetype 'of compound being reacted. Care should be taken to avoid too rapidan elevation of temperature since betalactones readily lose carbondioxide and form unsaturated hydro-carbons. The temperature may be aslow as --40 C. or as high as 50 C., but generally a temperature withinthe range of C. to 30 C. is preferred. Formaldehyde, for example, willreact with ketene within the temperature range of 0 to 50 C. whileacetone reacts at a temperature of from to 40 C.

Solvents, such as benzene, toluene, heptane, dioxane, ethyl ether,isopropyl ether, carbon tetrachloride, carbon bisulfide and the like,may or may not be used. In order to avoid separation of a solvent afterthe reaction has been completed, it is preferred to use a solution ofthe lactones produced from a previous run.

When an aldehyde is the carbonyl compound to be reacted, a more uniformprocess usually results if the ketene and aldehyde, in gaseous form andin substantially equimolar quantities, are passed into a stirredsolution of the metallic perchlorate in the lactone, while in othercases the gaseous ketene may be passed into a stirred solution of themetallic perchlorate catalyst, carbonyl compound, and lactone. However,it is not necessary always to use a gaseous aldehyde or a liquid ketone,diketone, or keto-ester. The temperature at which the condensation takesplace is the critical factor to be considered and it is, therefore, tobe understood that my process may be batchwise or continuous, or may beperformed in the liquid or vapor phase. When a. continuous process isused, any of the conventional apparatus available to the art for suchurposes may be employed. The catalyst may be supported on some inertsolid carrier therefor, and the flow of reactants may be counter-currentor otherwise. I prefer, however, when using a continuous process tocarry out my invention in the manner described in the copendingapplication of Hugh J. Hagemeyer and Delmer C. Cooper, Serial No.660,286, filed April 6, 1946. The pressures may be atmospheric orsuperatmospheric. If the ketene has been secured by the pyrolysis ofacetic acid, it may be advantageous to carry out the process in ascrubber-type reactor. Such a process is described in the copendingapplication of Herbert G. Stone, Serial No. 660,285, filed April 6,1946.

In some instances the beta-lactone may be distilled directly from theneutralized reaction mixture. However, when the lactone of anolefiniccarbonyl compound has been prepared, ordinarily such a mode ofseparation cannot be realized even under diminished pressures, sincedecarboxylization of the formed lactone may follow. Here an extractionor separation by gravity is indicated. When the lactone of a low-boilingcarbonyl compound, such as formaldehyde, acetaldehyde, etc. has beenformed, the lactone may be separated by flash distillation, i. e.,passing the warm reaction mixture into a heated chamber under reducedpressure, the low-boiling components thereof being distilled off, and aresidue consisting primarily of the desired lactone remaining. Thelactone may then be further purified by flash distillation under reducedpressures, or used without purification as a, solvent for a subsequentcondensation. This lactone solution need not correspond to the lactonebeing produced, however for practical purposes it is preferred to use alactone solution which corresponds to the lactone being formed. Whendesired, the lactone solvent and formed lactone need not correspond, ifthe lactone solution may be separated from the formed lactone byfractional distillation or if the mixture of lactones is intended to beutilized without purification in the preparation of other compounds suchas synthetic resins, polymers and the like.

The following examples are given to further characterize my invention:

Example I.Preparation of beta-propz'onlactone CHzCHz-(|1=O Gaseousketene and gaseous formaldehyde are mixed in approximately equimolarratios and are led into a stirred solution of .2 g. zinc perchlorate in50 g. beta-propionlactone, maintained at a temperature of 0-15 C. Thepassage of the gaseous reactants into the catalyst solution is continueduntil 10 g. moles of each reactant has been added. The reaction mixtureis then stirred with .5 g. sodium carbonate in 2 cc. water to neutralizethe catalyst. The product is subjected to a high vacuum flashdistillation to remove the catalyst. After re-distilling, a '70 to yieldof betapropionlactone boiling at 37 to 40 C., 4 mm. pressure isobtained. In a similar manner betabutyrolactone was prepared by reactingketene with acetaldehyde using zinc perchlorate as a catalyst, anexcellent yield bein attained. The formula for beta-butyrolactone is:

CHaCHCH2IC=O Example II.-Preparation of beta-metyl-betabutyrolactoneZinc perchlorate (0.5 g.) is dissolved in 200 cc. acetone and ketene ispassed through the solution at 2030 C. with efficient stirring. After 1mol of ketene has been passed in, the catalyst is neutralized by adding0.5 g. sodium carbonate in 1 cc. water. The product is decanted from theresidue and distilled in vacuum. A yield of 45-50%betamethyl-beta-butyrolactone, based on the ketene consumed, isobtained.

Example III..-Preparation of beta-carboethomymethyl-beta-butyro'lactoneB. Pt. 54.5/20 mm.

Example IV.--Preparation of beta-acetylmethylbeta-butyrolactone Keteneis passed into 300 g. acetyl acetone containing 1.0 g. magnesiumperchlorate. The temperature is maintained at 15-20 C. After 2 molsketene have been passed into the solution, the catalyst is neutralizedby adding 1 g. sodium carbonate in 2 cc. water. The product is decantedfrom the residue and distilled in vacuum. During the distillation, thelactone decomposes by losing CO2 to give 2-methyl-pentene-1-one-4 in30-40% yield, B. Pt. 127/'735. As a byproduct, some di-isopropenylmethane is obtained, B. Pt. 88/'735.

If desired, in lieu of securing the beta-lactone directly from theneutralized reaction mixture, it is possible to hydrolyze thebeta-lactone to a hydroxy carboxylic acid and subsequently dehydratethis acid to its corresponding unsaturated derivative. For example:

6 where R and R" represent hydrogen or a hydrocarbon radical.

Ezrample V.Preparation of beta, beta-dimethyl acrylic acid CH3 C=CHOOOHIn this example, the lactone was not separated from the reactionmixture, but was hydrolyzed by steam distillation to the unstablebeta-hydroxy acid:

I CH; OH

which was then dehydrated to the dimethyl acrylic acid.

Calcium perchlorate (.5 g.) is dissolved in 150 cc. of acetone andketene is passed through the solution at 20 to 30 C. with efficientstirring. After one mole of ketene has been passed in, the acetonesolution is poured into cc. of 15% hydrochloric acid. The mixture isthen steam distilled. After the acetone and most of the water has beenremoved, crystals of dimethyl acrylic acid begin to form in thecondenser. The product is collected by extracting from the watersolution with ether to give a yield of 40 to 50% based on the keteneconsumed. After recrystallizing from water, the dimethyl acrylic acidtitrated to an equivalent weight of 99.5; theoretical equivalent Weightwas 100.

Example VI .-Preparation of beta-ethylcrotom'c acid CH3C=CHCOOH Methylethyl ketone is treated with ketene using magnesium perchlorate ascatalyst as described in Example V above. A yield of 50 to 60% betaethyl crotonic acid is obtained based on the amount of ketene consumed.

By selecting different carbonyl compounds it is possible to prepareother beta-lactones. For example, by replacing the formaldehyde of EX-ample I or the acetone of Example II by 1.0 g. moles of butyraldehyde,beta-caprolactone having the following formula was produced:

Similarly it is possible to obtain beta-carbomethoXymethy1-,beta-butyrolactone by passing ketene into a stirred solution of zincperchlorate, methyl acetoacetate and a solvent for the reactants asdescribed above. The reaction is illustrated as follows:

H I! CHaCCHzC-O CH3 CH=C==O Methyl acetoacetate Ketene 0 C Hz 0 0 0 HaCHaC-CH2(|3=O O Beta-carbomethoxymethyl-beta-butyrolactoneBeta-propionylmethyl-beta-butyrolactone may be attained by passingketene into a stirred solution of zinc, magnesium, 'or cobaltperchlorate and propionyl acetone. This reaction is:

propionylacetone Ketene Bcta-propionylmethyl-beta-butyrolactone Thebeta-lactones of my invention, which are attained with difficulty byusing the Friedel- Crafts type catalyst of the prior art, are valuableintermediates for the preparation of unsaturated acids, hydroxy acids,unsaturated esters, amides, or nitriles.

I claim:

1. A process for preparing p-lactones which comprises reacting attemperature of from 40 C, to 50 C. a ketene having the formula:

wherein R and R1 each represents a member selected from the groupconsisting of a hydrogen atom, a methyl group, an ethyl group and aphenyl (CeI-I) group, with a carbonyl compound selected from the grouprepresented by the four general formulas:

Rr 2)m1C-O Rs wherein R2 represents a member selected from the groupconsisting of a hydrogen atom, an alkyl group having the formula CnH2n+1wherein n is a positive integer from 1 to 4, a benzyl group, afi-phenylethyl group, and a phenyl group (CsH5), R3 and R4 eachrepresents a member selected from the group consisting of an alkyl grouphaving the formula CnHM-i-I wherein n is a positive integer from 1 to 4,a benzyl group, a 5- phenylethyl group and a phenyl (C'eHs-) group, R5,R6, R7 and Rs each represents an alkyl group having the formula CnH2n+1wherein n is a positive integer from 1 to 4 and m represents a positiveinteger from 1 to 3 in the presence of a catalyst selected from thegroup consisting of zinc, copper, calcium, cadmium, magnesium, cobalt,nickel, stannous tin, and ferric perchlorates.

2. A process for preparing ,B-lactones which comprises reacting at atemperature of from -40 C. to 50 C. a ketene having the formula:

o=o=o B1 wherein R and R1 each represents a member selected from thegroup consisting of a hydrogen atom, a methyl group, an eth'yl group anda phenyl- (Carlagroup, with a carbonyl compound selected from the grouprepresented by the four general formulas:

wherein R represents a member selected from the group consisting of ahydrogen atom, an alkyl group having the formula CnH2n+1 wherein n is apositive integer from 1 to 4, a benzyl group, a ,8 phenylethyl group,and a phenyl group (Cs-H5), R3 and R4 each represents a member selectedfrom the group consisting of an alkyl group having the formula CnH2n+1wherein n is a positive integer from 1 to 4, a benzyl group, a,IR-phenylethyl group and a phenyl (CeH5-) group, R5, R5, R7 and Rs eachrepresents an alkyl group having the formula CnH2n+1 wherein n is apositive integer from 1 to 4 and m represents a positive integer from 1to 3 in the presence of from 0.01% to 2% by weight based on the carbonylcompound of a catalyst selected from the group consisting of zinc,copper, calcium, cadmium, magnesium, cobalt, nickel, stannous tin, andferric perchlorates, and in the presence of an inert solvent.

3. A process for preparing fi-la-ctones which comprises reacting at atemperature of from 40 to 50 C. a ketene having the formula:

wherein R and R1 each represents a member selected from the groupconsisting of a hydrogen atom, a methyl roup, an ethyl group and aphenyl (CsI-I5) group, with a carbonyl compound selected from the grouprepresented by the four general formulas:

wherein R2 represents a member selected from the group consisting of ahydrogen atom, an alkyl group having the formula CnH2n+1 wherein n is apositive integer from 1 to 4, a benzyl group, a fi-phenylethyl group,and a phenyl group (C6H5--), R3 and R4 each represents a member selectedfrom the group consisting of an alkyl group having the formula CnH2n+1wherein n is a positive integer from 1 to 4, a benzyl group, afl-phenylethyl group and a phenyl (CeH5) group, R5, Re, R? and Rs eachrepresents an alkyl group having .the formula CnI-I2n+1 wherein n is apositive integer from 1 to 4 and m represents a positive integer from 1to 3 in the presence of from 0.01% to 2% by weight based on the carbonylcompound of a catalyst selected from the group consisting of zinc,copper, calcium, cadmium, magnesium, cobalt, nickel, stannous tin, andferric perchlorates, and in the presence of a fi-lactone whichcorresponds to the lactone being formed.

4. A process for preparing a B-Jactone which comprises reacting at atemperature offrom -4=0 C. to 50 C- ketene (CH2=C=O) with a car- 9 bonylcompound selected from the group represented by the four generalformulas:

O 0 II II II where R2 represents a member selected from the groupconsisting of a hydrogen atom, an alkyl group having the formula CnH2n+1wherein n is a positive integer from 1 to 4, a benzyl group, afi-phenylethyl group, and a phenyl group (CsH--), R3 and R4 eachrepresents a member selected from the group consisting of an alkyl grouphaving the formula CnHZn-l-l wherein n is a positive integer from 1 to4, a benzyl group, a B-phenylethyl group and a phenyl (CcH5-) group, R5,R6, R1 and Rs each represents an alkyl group having the formulaCnHZn-l-l wherein n is a positive integer from 1 to 4, and m representsa positive integer from 1 to 3 in the presence of a catalyst selectedfrom the group consisting of Zinc, copper, calcium, cadmium, magnesium,cobalt, nickel, stannous tin, and ferric perchlorates.

wherein R2 represents a member selected from the group consisting of ahydrogen atom, an alkyl group having the formula CnI-I'znH wherein n isa positive integer from 1 to 4, a benzyl group, a c-phenylethyl group,and a phenyl group (C6H5-), R3 and R4 each represents a member selectedfrom the group consisting of an alkyl group having the formula CnH2n+1wherein n is a positive integer from 1 to 4, a benzyl group, aB-phenylethyl group and a phenyl (CsH5-) group, R5, R6, R7 and Rs eachrepresents an alkyl group having the formula CnH2n+1 wherein n is apositive integer from 1 to 4 and m represents a positive integer from 1to 3 in the presence of from 0.01% to 2% by weight based on the carbonylcompound of a catalyst selected from the group consisting of zinc,copper, calcium, cadmium, magnesium, cobalt, nickel, stannous tin, andferric perchlorates, and in the presence of an inert solvent.

. 6. A process for preparing fi-lactones which comprises reacting at atemperature of 40 C. to 50 C. a ketene having the formula:

o=o=o R1 wherein R and R1 each represents a member selected from thegroup consisting of a hydrogen atom, a methyl group, an ethyl group anda phenyl group (CsH5) with an aldehyde represented by the formula:

wherein R2 represents an alkyl group of the formula CnH2n+1 wherein n isa positive integer of 1 to 4, in the presence of from 0.01% to 2% byweight based upon the aldehyde used as a catalyst selected from thegroup consisting of zinc, copper, calcium, cadmium, magnesium, cobalt,nickel, stannous tin, and ferric perchlorates, in the presence of aninert solvent.

'7. A process for preparing li-lactones which comprises reacting at atemperature of -40 C. to 50 C. a ketene having the formula:

o=o=o R1 wherein R and R1 each represents a member selected from thegroup consisting of a hydrogen atom, a methyl group, an ethyl group anda phenyl group (CcH5-) with an aldehyde represented by the formula.

, V wherein R2 represents analkyl group of the formula CnH2n+1 wherein nis a positive integer of 1 to 4, in the presence of from 0.01% to 2% byweight based upon the aldehyde used of a catalyst selected from thegroup consisting of zinc, copper, calcium, cadmium, magnesium, cobalt,nickel, stannous tin, and ferric perchlorates, and in the presence of afi-lacton which corresponds to the lactone being formed.

8. A process for preparing c-lactones which comprises reacting at atemperature of 40 C. to 50 C. a ketene having the formula:

o=o=0 R1 wherein R and R1 each represents a member selected from thegroup consisting of a hydrogen atom, a methyl group, an ethyl group anda phenyl group (CcH5-) with a ketone represented by the formula:

0:0 Ra wherein R3 and R4 each represents a member selected from thegroup consisting of an alkyl group of the formula CnH2n+l wherein n is apositive integer from 1 to 4, a benzyl group, a c-phenyl ethyl group,and a phenyl group (CeH5-) in the presence of a catalyst selected fromthe group consisting of zinc, copper, calcium, cadmium, magnesium,cobalt, nickel, stannous tin, and ferric perchlorates, in the presenceof an inert solvent.

9. A process for preparing B-lactones which comprises reacting at atemperature of -40 C. to 50 C. a ketene having the formula:

o=o=o R1 wherein R and R1 each represents a member selected from thegroup consisting of a hydrogen atom, a methyl group, an ethyl group anda phenyl group (CsHs-) with a ketone represented by the formula:

11 wherein R3 and R4 each represents a member selected from the groupconsisting of an alkyl group of the formula C11H2n+1 wherein n is apositive integer from 1 to 4, a benzyl group, a c-phenyl ethyl group,and a phenyl group (CsH-) in the presence of from 0.01% to 2% by weightbased on the ketone of a catalyst selected from the group consisting ofzinc, copper, calcium, cadmium, magnesium, cobalt, nickel, stannous tin,and ferric perchlorates, in the presence of an inert solvent.

10. A process for preparing a fi-lactone which comprises reacting at atemperature of from 40 C. to 50 C. ketene (CI-Iz=C=O) with a ketonerepresented by the formula:

wherein R3 and R4. each represents a member selected from the groupconsisting of an alkyl group of the formula CnHZTH-l wherein n is apositive integer from 1 to 4, a benzyl group, a ,B-phenyl ethyl group,and a phenyl group (CsH5-) in the presence of from 0.01% to 2% by weightbased on the ketone of a catalyst selected from the group consisting ofzinc, copper, calcium, cadmium, magnesium, cobalt, nickel, stannous tin,and ferric perchlorates, in the presence of an inert solvent.

11. A process for preparing B-lactones which comprises reacting ketene(CI-Iz=C=O) with an aldehyde represented by the formula:

wherein R2 represents an alkyl group of the formula CnI-I2'n+1 where nis a positive integer of from 1 to 4, in the presence of from 0.01% to2% based on the weight of the aldehyde used of a catalyst selected fromthe group consisting of zinc, copper, cadmium, calcium, magnesium,cobalt, nickel, stannous tin and ferric perchlorates at a temperature offrom -40 C. to +50 C., in the presence of an inert solvent.

12. A process of preparing fi-propiolactone which comprises reactingketene with formaldehyde in the presence of from about 0.01% to 2% basedon the weight of formaldehyde of a catalyst selected from the groupconsisting of zinc, copper, calcium, cadmium, magnesium, cobalt, nickel,stannous tin, and ferric perchlorates at a temperature of from O-15 C.

13. A process for preparing p-propiolactone which comprises reactingketene with formaldehyde in the presence of from 0.01% to 2% zincperchlorate based on the weight of formaldehyde and at a temperature offrom 0-15 C.

14. A process for preparing c-propiolactone which comprises reactingketene with formaldehyde in the presence of from 0.01% to 2% zincperchlorate based on the weight of formaldehyde and at a temperature offrom 0-15 C. in the presence of an inert solvent.

.15. A process for preparing ,c-propiolactone which comprises reactingat a temperature of from 015 C. ketene with formaldehyde in the presenceof from about 0.01% to 2% based on the weight of formaldehyde of acatalyst selected from the group consisting of zinc, copper, calcium,cadmium, magnesium, cobalt, nickel, stannous tin, and. ferricperchlorates in the presence of c-propiolactone as a solvent.

16. A process for preparing ,B-butyrolactone which comprises reacting ata temperature of from 0-15 C. ketene with acetaldehyde in the presenceof a catalyst selected from the group consisting of zinc, copper,calcium, cadmium, magnesium, cobalt, nickel, stannous tin, and ferricperchlorates.

17. A process for preparing B-butyrolactone which comprises reacting ata temperature of from 0-15 C. ketene with acetaldehyde in the presenceof from about 0.01% to 2% based on the weight of acetaldehyde of zincperchlorate and in the presence of an inert solvent.

18. The process for preparing B-lactones which comprises reacting at atemperature of from --40 C. to 0. ketene (CH2=C=O) with acetone in thepresence of 0.01% to 2% by weight based on the acetone used of acatalyst selected from the group consisting of zinc, copper, calcium,cadmium, magnesium, cobalt, nickel, stannous tin, and ferricperchlorates in the presence of an inert solvent.

19. The process for preparing B-lactones which comprises reacting at atemperature of from 40 C. to 50 C. ketene (CH2=C=O) with acetone in thepresence of 0.01% to 2% by weight based on the \acetone used of acatalyst selected from the group consisting of zinc, copper, calcium,cadmium, magnesium, cobalt, nickel, stannous tin, and ferricperchlorates.

JOHN R. CALDWELL.

No references cited.

